Internal-combustion engine



Dec. 14 1926.

w. o. H. SAUER INTERNAL COMBUSTION ENGINE Filed April 8. 1922 Patented Dec. 14, 1926.

UNITED, STATES PATENT OFFICE.

WILLIAM OSWALD HUGO SAUEB, 01E PITTSBURGH, PENNSYLVANIA.

INTERNAL-COMBUSTION ENGINE.

Application filed April 8,

mixmg or atomizing of the gas fuel, whereby the heavier oil fuels are more thoroughly disintegrated and mixed with the air.

To these ends the invention consists, generally stated, in the provision of means for feeding fuel in which the maximum quantity of the explosive charge will be considerably less than the total piston displacement at atmospheric pressure, preferably a fractional charge having a volume of one-half the total displacement of the piston. The invention herein is described and shown to operate on a maximum charge having a vol ume of substantially one-half of the total piston displacement, assuming the charge to be at atmospheric pressure, or slightly above, at the beginning of the compression of the charge. 1 f

In the accompanying drawings, Fig. 1 is a vertical sectional view, mainly in diagram, showing a typical gas fuel engine having my invention applied thereto; Fig. 2 is a diagram of the timing of the inlet and exhaust valves as used with my invention; and Fig. 3 is a diagram or indicator card showing the power gained. a

In Fig. 1 I have illustrated my invention as applied to an engine which is typical as used with auto vehicles, and which comprises such parts as the cylinder body 2, the piston 3, connecting rod 3 the crank 4, crank shaft inlet valve 5, exhaust valve 6, inlet manifold 7, and the carburetor 8, the'general design of which, in all respects, is the same as commonly used in engines of this type,

with the following exceptions:

I have provided an exhaust port consider: ably larger in area than is the common practice, though itmay be of the same size as the intake port, and have modified the fuel passage between the carburetor and the cyl-. inder by inserting between the intake manifold and the carburetor a restricting or retarding device 9. This deviceis-shown as 1922. Serial no. 550,900.

an attachment made in the form of a Venturi tube which may convenientl bolted to the lower flange of the manifol and to the upper flange of the carburetor. However, I do not confine myself to this particular arrangement, as other means for creating resistance to the, flow of the fuel in the intake passage may be employed. For instance, the carburetor itself may be constructed to give resistance to the flow of the fuel in the manner similar to the device 9. Or, the carburetor inlet may be restricted or obstructed in any suitable manner, or a throttle valve maybe installed in the pas-.

sage between the carburetor and the cylinder, and the resistance made adjustable, or, in the case of poppet valves, by making the valve small enough, or by reducing the valve passage, or by increasing the 'dlameter' of the valve stem, or decreasing the valve lift. A preferable arrangement, especially for valve-in-the-head engines wlth poppet valves, corresponds to Fig. 1 of the drawing, in which the inlet valve is made smaller than the exhaust valve in order to gain more space for the latter and reduce the exhaust back pressure, while the main resistance is placed at an equidistant point such as, for instance, the Venturi connection 9 where the inlet manifold branches out to the several cylinders and does not interfere with inter-communication of charge between cylinders, the latter being necessary when the throttle is opened beyond the critical position for any speed, as will hereinafter appear.

In addition to the modifications in the fuel passage, as above mentioned, the timing of the inlet and exhaust valves are arranged diiferently, as compared with the common practice, to permit the exploded charge to have a greater space in which to expand in respect to the power stroke. That is to say, the advance of the exhaust valve opening with respect to the lower dead cen ter is materially reduced, the angular advance being substantially 30 degrees, as compared with 46 degrees as in the common practice. However, I do not wish to limit the roller 12 of the valve stem. The 11 is rotated at one half the speed of the shaft 4, and the cam 10 is of such form and so disposed circumferentially on the. shaft 11 that the valve 5 .is held open during the intake stroke, as shown in Fig. 1, and is maintained in open position during substantially one half of the compression stroke, as shown in Fig. 2. This arrangement insures that a maximum charge of only about one half the amount of piston displacement at atmospheric pressure is retained in the cylinder, thus avoiding excessive compression and reducing the danger of preignition, as the compression space above the piston, when in the upper dead center position, is only adapted in size to the maximum charge, in order to give the highest possible compres sion. The angular retardation of the closing of the inlet valve 5 with respect to the lower dead center position of the piston 3 is over 90 degrees, as compared with the usual setting of 30 degrees in present practice. The retardation of the closing of the inlet valve 5 is shown on the drawing as 97 degrees, but it will be understood that the angularity may be either greater or less, as conditions will require. The point is that I insure that the volume of charge to be compressed shall be about one half of the piston displacement.

In order to get a clearer understanding of the actionof the restricting device 9 in the performance of this engine it must be borne in mind that the resistance for any fixed opening in the venturi with the throttle wide open increases about as the square of the quantity of gas flow, and is therefore directly a function of the speed ofthe engine. In starting and at low speed with. the

v throttle fully open the cylinder will take up a full charge ofexplosive mixture equal to the piston displacement at atmospheric pressure, expelling half of it again on the compression stroke on account of the definite and fixed timing of the inlet va-lve which always stays open for one'half of the compression stroke, as shown in Fig. 2. Asthe engine speeds up with the throttle fully open and the gas flow increases, the flow resistance (as I call 1t) will increase also until at some high speed the cylinder charge will be one half of the total piston displacement at atmospheric pressure at which speed no surplus charge will be expelled back again through the inlet valve, as thetotal'charge drawn in is only one half. The same result can now be accomplished for any lower speed-by a certain setting of the throttle, called critical setting,'thereby inserting additional resistance, which added to the lower flow resistance at said lower speed with the throttle wide open, will give a cylinder charge of one half of the piston displacement at atmospheric, pressure without any surplus charge being expelled back againthrough the inlet valve. As there is a different critical setting for every speed below high speed, or inversely a different critical s eed for every setting of the throttle, it will e evident that for any particular constant speed under con sideration a further opening of the throttle beyond this critical setting will cause a surplus charge to be expelled back again through the inlet valve, while a further closing of the throttle will decrease the charge below one half of the piston displacement at atmospheric pressure.

In operation the engine is controlled for speed by the throttle as in present practice, except that it contains in addition a self governing feature, whereby any variation in load. is automatically regulated without changing the throttle setting. Assuming the throttle to be set and the engine running at a certain load and speed, the latter being above critical speed. As the load decreases the speed will increase, but owing to the flow resistance increasing with the speed, the

cylinder charge will be less and in proportion to-the load. In a similar manner when the load increases the speed will decrease, but owing to the flow resistance decreasing with the speed thecylinder charge will be greater than at first and in proportion to the load. With further increase in load the speed will drop until the critical speed is reached,,

at which the cylinder charge is one half of the piston displacement at atmospheric pressure and below which the'charge will not increase, as any surpllus charge is expelled back again through t e inlet valve. It, must be pointed out however that in the normal operation of this engine no surplus charge will be present, except possibly in starting and at low s eeds when overloaded, as the throttle openmg is usually kept'below the critical setting, which latter corresponds to full throttle opening in present practice.

. Referring to Fig. 3 theline A B represents the normal length of piston stroke, and the line D represents the .rived from expansion of a ful cylinder charge in an ordinary present day engine. If piston and exhaust valves were so arranged that the expansion could be continued for the distance B C equal to A B, about 33 additional power would be secured from a given ex losion, which is shown by the shaded portion above lines B C. In my invention this additional power is secured from a given amount of explosive charge equal. to one half of the piston displacement at atmospheric pressure, but expanded to twice the volume, which is equivalent to twice the power stroke in the ordinary engine or the distance A C in Fig. 3, and a diagram of the power produced is therefore substantially identical to Fig. 3.

If the valve 5 and the operating mechaower denism therefor were employed independently of a restricted inlet passage, the fuel charge in the cylinder with the throttle wide open would be the same at all speeds and substantially equal to one half of the piston displacement atv atmospheric pressure. With the arrangement above described and the throttle wide open, the cylinder charge will also be constant and equal to the same quantity, .but the amount ofdischarge expelled back through the inlet valve will decrease as the speed increases, until at some high speed it will be zero and above which speed the cylinder charge will diminish until the speed.

limit is reached.

As a result of the greater expansion of the gas in the power stroke, more heat is converted into mechanical energy, leaving less for dissipation through the water jacket and exhaust manifold, so that air cooling with this engine may be used to advantage.

On account of the much smaller amount of burnt gases to be expelled through the exhaust valve, as compared with the piston displacement, there will be considerably less back pressure to thepiston, thus permitting the opening of the exhaust valve to be delayed for a longer period than is .possible at present.

By reason of the action of the restricting 3o device 9 in alternately contracting and ex-" panding the fuel mixture when passing through it, the heavier and the less volat le oil 'fuels will be more thoroughly dlsln' tegrated due to the expansion.

' From the/above description it will be seen that I have provided an engine in which the maximum exploded charge has greater expansion, as compared with the common practice, and greater duration of expansive energy applied to the piston on the power stroke, thus making for more eflicient'performance and smoother delivery of power.

What I claim is:

The combination with an internal com- 'bustion engine, of a fuel inlet passage, means slower speeds.

WILLIAM OSWALD HUGO SAUER.

quantity when the engine is running at 55 

